Flexible display device including a flexible substrate having a bending part and a conductive pattern at least partially disposed on the bending part

ABSTRACT

A flexible display device including a flexible substrate and a conductive pattern. The flexible substrate includes a bending part in which a bending occurs. At least a portion of the conductive pattern is disposed on the bending part and the conductive pattern includes grains. Each grain has a grain size of about  10  nm to about  100  nm.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Division of U.S. patent application Ser. No.15/075,844, filed on Mar. 21, 2016, which claims priority from and thebenefit of Korean Patent Application No. 10-2015-0076440, filed on May29, 2015 and No. 10-2015-0171680, filed on Dec. 3, 2015, all of whichare hereby incorporated by reference for all purposes as if fully setforth herein.

BACKGROUND Field

Exemplary embodiments relate to a flexible display device and a methodof manufacturing the same. More particularly, exemplary embodimentsrelate to a flexible display device capable of a crack occurring due tobending, and a method of manufacturing the flexible display device.

Discussion of the Background

A display device displays various images on a display screen to providea user with information. In recent years, a display device, which isbendable, has been developed. As opposed to a flat panel display device,a flexible display device is capable of being folded, rolled, or curvedas a paper. The flexible display device capable of being deformed invarious shapes is made for the user's convenience of moving or handling.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the inventive concept,and, therefore, it may contain information that does not form the priorart that is already known in this country to a person of ordinary skillin the art.

SUMMARY

Exemplary embodiments provide a flexible display device capable ofpreventing a crack from occurring due to bending.

Exemplary embodiments also provide a method of manufacturing theflexible display device.

Additional aspects will be set forth in the detailed description whichfollows, and, in part, will be apparent from the disclosure, or may belearned by practice of the inventive concept.

An exemplary embodiment discloses a flexible display device including aflexible substrate and a conductive pattern. The flexible substrateincludes a bending part. The conductive pattern includes a plurality ofgrains and at least a portion of the conductive pattern is disposed onthe bending part. Each of the grains has a grain size of about 10 nm toabout 100 nm.

An exemplary embodiment also discloses a flexible display deviceincluding a flexible display panel and a touch screen panel. Theflexible display panel includes a panel bending part. The touch screenpanel includes a touch bending part and is disposed on the flexibledisplay panel. At least one of the flexible display panel and the touchscreen panel includes a conductive pattern including a plurality ofconductive pattern layers, each having a grain size of about 10 nm toabout 100 nm, and at least one of the panel bending part and the touchbending part includes the conductive pattern.

An exemplary embodiment also discloses a flexible display deviceincluding a flexible display panel and a touch screen panel. The touchscreen panel includes a touch bending part. The touch bending partincludes a sensing electrode having a mesh structure; the sensingelectrode includes a plurality of sensing electrode layers; and thesensing electrode layers include a same material.

An exemplary embodiment also discloses a method of manufacturing aflexible display device, including preparing a flexible substrate andproviding a conductive pattern on the flexible substrate, the conductivepattern having a grain size of about 10 nm to about 100 nm.

The foregoing general description and the following detailed descriptionare exemplary and explanatory and are intended to provide furtherexplanation of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the inventive concept, and are incorporated in andconstitute a part of this specification, illustrate exemplaryembodiments of the inventive concept, and, together with thedescription, serve to explain principles of the inventive concept.

FIG. 1A, FIG. 1B, and FIG. 1C are perspective views illustrating aflexible display device according to an exemplary embodiment of thepresent disclosure.

FIG. 2A, FIG. 2B, FIG. 2C, and FIG. 2D are cross-sectional views takenalong a line I-I′ of FIG. 1B.

FIG. 3A is a perspective view showing a flexible display deviceaccording to an exemplary embodiment of the present disclosure.

FIG. 3B is a cross-sectional view showing a line included in a flexibledisplay device according to an exemplary embodiment of the presentdisclosure.

FIG. 3C is a cross-sectional view showing an electrode included in aflexible display device according to an exemplary embodiment of thepresent disclosure.

FIG. 4A is a perspective view showing a flexible display deviceaccording to an exemplary embodiment of the present disclosure.

FIG. 4B is a cross-sectional view taken along a line of FIG. 4A.

FIG. 4C is a cross-sectional view showing a first line included in aflexible display device according to an exemplary embodiment of thepresent disclosure.

FIG. 4D is a cross-sectional view showing a second line included in aflexible display device according to an exemplary embodiment of thepresent disclosure.

FIG. 5A, FIG. 5B, and FIG. 5C are perspective views showing a flexibledisplay device according to an exemplary embodiment of the presentdisclosure.

FIG. 6A is a circuit diagram showing one pixel of pixels included in aflexible display panel according to an exemplary embodiment of thepresent disclosure.

FIG. 6B is a plan view showing one pixel of pixels included in aflexible display panel according to an exemplary embodiment of thepresent disclosure.

FIG. 6C is a cross-sectional view taken along a line of FIG. 6B.

FIG. 7A is a cross-sectional view showing a flexible display deviceaccording to an exemplary embodiment of the present disclosure.

FIG. 7B is a plan view showing a touch screen panel included in aflexible display device according to an exemplary embodiment of thepresent disclosure.

FIG. 8A is a plan view showing a flexible display device according to anexemplary embodiment of the present disclosure.

FIG. 8B is a plan view showing a touch screen panel included in aflexible display device according to an exemplary embodiment of thepresent disclosure.

FIG. 9A is a cross-sectional view showing a sensing electrode includedin a touch screen panel according to an exemplary embodiment of thepresent disclosure.

FIG. 9B is a cross-sectional view showing a line included in a touchscreen panel according to an exemplary embodiment of the presentdisclosure.

FIG. 10 is a flowchart showing a method of manufacturing a flexibledisplay device according to an exemplary embodiment of the presentdisclosure.

FIG. 11A and FIG. 11B are SEM images showing first to fourth embodimentexamples and first and second comparison examples.

FIG. 12 is a photograph showing a cross section of third and fourthembodiment examples and first and second comparison examples.

FIG. 13 is a photograph showing a disconnection in first and thirdcomparison examples due to inner and outer bendings.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of various exemplary embodiments. It is apparent, however,that various exemplary embodiments may be practiced without thesespecific details or with one or more equivalent arrangements. In otherinstances, well-known structures and devices are shown in block diagramform in order to avoid unnecessarily obscuring various exemplaryembodiments.

In the accompanying figures, the size and relative sizes of layers,films, panels, regions, etc., may be exaggerated for clarity anddescriptive purposes. Also, like reference numerals denote likeelements.

When an element or layer is referred to as being “on,” “connected to,”or “coupled to” another element or layer, it may be directly on,connected to, or coupled to the other element or layer or interveningelements or layers may be present. When, however, an element or layer isreferred to as being “directly on,” “directly connected to,” or“directly coupled to” another element or layer, there are no interveningelements or layers present. For the purposes of this disclosure, “atleast one of X, Y, and Z” and “at least one selected from the groupconsisting of X, Y, and Z” may be construed as X only, Y only, Z only,or any combination of two or more of X, Y, and Z, such as, for instance,XYZ, XYY, YZ, and ZZ. Like numbers refer to like elements throughout. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items.

Although the terms first, second, etc. may be used herein to describevarious elements, components, regions, layers, and/or sections, theseelements, components, regions, layers, and/or sections should not belimited by these terms. These terms are used to distinguish one element,component, region, layer, and/or section from another element,component, region, layer, and/or section. Thus, a first element,component, region, layer, and/or section discussed below could be termeda second element, component, region, layer, and/or section withoutdeparting from the teachings of the present disclosure.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper,” and the like, may be used herein for descriptive purposes, and,thereby, to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the drawings. Spatiallyrelative terms are intended to encompass different orientations of anapparatus in use, operation, and/or manufacture in addition to theorientation depicted in the drawings. For example, if the apparatus inthe drawings is turned over, elements described as “below” or “beneath”other elements or features would then be oriented “above” the otherelements or features. Thus, the exemplary term “below” can encompassboth an orientation of above and below. Furthermore, the apparatus maybe otherwise oriented (e.g., rotated 90 degrees or at otherorientations), and, as such, the spatially relative descriptors usedherein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments and is not intended to be limiting. As used herein, thesingular forms, “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. Moreover,the terms “comprises,” “comprising,” “includes,” and/or “including,”when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, components, and/orgroups thereof, but do not preclude the presence or addition of one ormore other features, integers, steps, operations, elements, components,and/or groups thereof.

Various exemplary embodiments are described herein with reference tosectional illustrations that are schematic illustrations of idealizedexemplary embodiments and/or intermediate structures. As such,variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, exemplary embodiments disclosed herein should not beconstrued as limited to the particular illustrated shapes of regions,but are to include deviations in shapes that result from, for instance,manufacturing. The regions illustrated in the drawings are schematic innature and their shapes are not intended to illustrate the actual shapeof a region of a device and are not intended to be limiting.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure is a part. Terms,such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and will not be interpreted in anidealized or overly formal sense, unless expressly so defined herein.

FIGS. 1A, 1B, and 1C are perspective views showing a flexible displaydevice 10 according to an exemplary embodiment of the presentdisclosure.

Referring to FIGS. 1A, 1B, and 1C, the flexible display device 10includes a flexible substrate FB and a conductive pattern CP. Theconductive pattern CP is disposed on the flexible substrate FB in afirst direction DR1. The term of “flexible” used herein means that thesubstrate is bendable, and thus, the flexible substrate FB may becompletely folded or partially bent. The flexible substrate FB mayinclude, but is not limited to, a plastic material or an organicpolymer, e.g., polyethylene (PET), polyethylene naphthalate (PEN),polyimide, polyether sulfone, etc. The material for the flexiblesubstrate FB is selected in consideration of mechanical strength,thermal stability, transparency, a surface smoothness, ease of handling,water repellency, etc. The flexible substrate FB may be transparent.

The flexible display device 10 is operated in a first mode or a secondmode. The flexible substrate FB includes a bending part BF and anon-bending part NBF. The bending part BF is bent in the first mode withrespect to a bending axis BX extending in a second direction DR2 and isunbent in the second mode. The bending part BF is connected to thenon-bending part NBF. The non-bending part NBF is not bent in the firstand second modes. At least a portion of the conductive pattern CP isdisposed on the bending part BF. The term “bending” used herein meansthat the flexible substrate FB is curved in a specific shape as a resultof an external force.

Referring to FIGS. 1A and 1C, at least a portion of the flexiblesubstrate FB and the conductive pattern CP is bent in the first mode.Referring to FIG. 1B, the bending part BF is unbent in the second mode.

The first mode includes a first bending mode and a second bending mode.Referring to FIG. 1A, the flexible display device 10 is bent in onedirection with respect to the bending axis BX in the first bending mode.That is, the flexible display device 10 is inwardly bent in the firstbending mode. Hereinafter, when the flexible display device 10 is bentwith respect to the bending axis BX, a state in which a distance betweenportions, which face each other after the conductive pattern CP is bent,of the conductive pattern CP is less than a distance between portions,which face each other after the flexible substrate FB is bent, of theflexible substrates FB is referred to as an inner bending. In the innerbending state, a surface of the bending part BF has a first radius ofcurvature R1. The first radius of curvature R1 is in a range from aboutlmm to about 10 mm.

Referring to FIG. 1C, the flexible display device 10 is bent in adirection opposite to the one direction in FIG. 1A with respect to thebending axis BX in the second bending mode. That is, the flexibledisplay device 10 is outwardly bent in the second bending mode.Hereinafter, when the flexible display device 10 is bent with respect tothe bending axis BX, a state that a distance between portions, whichface each other after the flexible substrate FB is bent, of the flexiblesubstrate FB is less than a distance between portions, which face eachother after the conductive pattern CP is bent, of the conductive patternCP is referred to as an outer bending. In the outer bending state, asurface of the bending part BF has a second radius of curvature R2. Thesecond radius of curvature R2 may or may not be equal to the firstradius of curvature R1. The second radius of curvature R2 is in a rangefrom about 1 to about 10 mm.

In FIGS. 1A and 1C, when the flexible display device 10 is bent withrespect to the bending axis BX, the distance between the portions facingeach other of the flexible substrate FB is constant, but it should notbe limited thereto or thereby. That is, the distance between theportions facing each other of the flexible substrate FB may not beconstant. In addition, in FIGS. 1A and 1C, when the flexible displaydevice 10 is bent with respect to the bending axis BX, an area of oneportion of the portions of the bent flexible substrate FB may be equalto an area of the other portion of the portions of the bent flexiblesubstrate FB, but it should not be limited thereto or thereby. That is,the area of one portion of the portions of the bent flexible substrateFB may be different from the area of the other portion of the portionsof the bent flexible substrate FB.

FIGS. 2A to 2D are cross-sectional views taken along a line I-I′ of FIG.1B.

Referring to FIGS. 1A to 1C and 2A, at least the portion of theconductive pattern CP is disposed on the bending part. The conductivepattern CP includes a plurality of grains GR. The grains GR are crystalgrains obtained by regularly arranging component atoms. Each grain GRhas a grain size of about 10 nm to about 100 nm.

Hereinafter, the grain size may indicate an average of several particlediameters or a maximum particle diameter. In addition, the grain size ofeach grain GR may be in a range from about 10 nm to about 100 nm, theaverage of the grain sizes of the grains GR may be in a range from about10 nm to about 100 nm, or a representative value of the grain sizes maybe in a range from about 10 nm to about 100 nm.

When the grain size of the conductive pattern CP is less than about 10nm, a resistance of the conductive pattern CP increases, and thus, thepower consumption required to drive the flexible display device 10increases. When the grain size of the conductive pattern CP greater thanabout 100 nm, it is difficult to secure flexibility of the bending ofthe conductive pattern CP as a result of the large grain size. As aresult, a crack or a disconnection occurs in the conductive pattern CP,resulting in reduced reliability of the flexible display device 10.

In general, when the grain size of the conductive pattern CP becomessmall, the resistance of the conductive pattern CP increases and thepower consumption required to drive the flexible display device 10increases, but the flexible display device 10 may have flexibility sincethe flexibility is secured. On the contrary, when the grain size of theconductive pattern CP becomes large, the resistance of the conductivepattern CP decreases, but the crack or disconnection of the conductivepattern CP occurs since it is difficult to secure the flexibility.

The conductive pattern CP of the flexible display device 10 according tothe present exemplary embodiment has the grain size greater than orequal to about 10 nm and less than or equal to about 90 nm. Accordingly,the conductive pattern CP has the appropriate resistance to secureproper driving characteristics and improved flexibility. Therefore, thereliability of the flexible display device 10 is improved.

In the conductive pattern CP, about 200 grains to about 1200 grains arearranged within a unit area of about 1.0 square micrometers (μm²). Theterm of “within the unit area of about 1.0 square micrometers (μm²)”means that the unit area may be defined in an arbitrary area on a planesurface of the conductive pattern CP. When the number of the grains GRin the unit area of about 1.0 square micrometers (μm²) is less thanabout 200, it is difficult to secure bending flexibility. Thus, thecrack or disconnection of the connection pattern CP occurs and thereliability of the flexible display device 10 is reduced. In addition,when the number of the grains GR in the unit area of about 1.0 squaremicrometers (μm²) exceeds about 1200, the resistance of the conductivepattern CP increases, and thus, the power consumption required to drivethe flexible display device 10 increases.

The conductive pattern CP includes at least one of a metal, a metalalloy, and a transparent conductive oxide, but it should not be limitedthereto or thereby. The grains GR may be at least one of grains ofmetal, grains of metal alloy, and grains of transparent conductiveoxide.

The metal may include, but not limited to, at least one of Al, Cu, Ti,Mo, Ag, Mg, Pt, Pd, Au, Ni, Nd, Ir, and Cr.

The transparent conductive oxide may include, but is not limited to, atleast one of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide(ZnO), and indium tin zinc oxide (ITZO).

Referring to FIGS. 1A to 1C, and 2A to 2D, the conductive pattern CPincludes a plurality of conductive pattern layers CPL. The number of theconductive pattern layers CPL included in the conductive pattern CP maybe two, three, four, five, or six, but it should not be limited theretoor thereby. That is, the conductive pattern CP may include seven or moreconductive pattern layers CPL. The grains GR arranged in differentconductive pattern layers CPL are not connected to each other. That is,the grains are included in each of the conductive pattern layers CPL.

Each grain GR of the conductive pattern layers CPL has a grain size ofabout 10 nm to about 100 nm. When the grain size of the grains GR of theconductive pattern layers CPL is less than about 10 nm, a resistance ofthe conductive pattern layers CPL increases, and thus, power consumptionrequired to drive the flexible display device 10 increases. When thegrain size of grains GR of the conductive pattern layers CPL is greaterthan about 100 nm, it is difficult to secure flexibility of the bendingof the conductive pattern layers CPL as a result of the large grainsize. As a result, a crack or a disconnection occurs in the conductivepattern layers CPL, and reliability of the flexible display device 10 isreduced.

Each of the conductive pattern layers CPL has a thickness of about 10 nmto abut 150 nm. When the thickness of each of the conductive patternlayers CPL is less than about 10 nm, the number of interfaces of theconductive pattern layers CPL increases even though the overallthickness of the conductive pattern CP is not increased, and thus, theresistance of the conductive pattern CP increases. Accordingly, powerconsumption required to drive the flexible display device 10 increases.In addition, the reliability of the conductive pattern layers CPL may bereduced when each conductive pattern layer CPL is manufactured orprovided. When the thickness of each of the conductive pattern layersCPL is greater than about 150 nm, it is difficult to secure flexibilityof the conductive pattern layers CPL when the conductive pattern layersCPL are bent. As a result, a crack or a disconnection occurs in theconductive pattern layers CPL, and reliability of the conductive patternlayers CPL is reduced.

Each of the conductive pattern layers CPL may include at least one of ametal, a metal alloy, and a transparent conductive oxide, but it shouldnot be limited thereto or thereby.

The metal may include, but not limited to, at least one of Al, Cu, Ti,Mo, Ag, Mg, Pt, Pd, Au, Ni, Nd, Ir, and Cr.

The transparent conductive oxide may include, but not limited to, atleast one of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide(ZnO), and indium tin zinc oxide (ITZO).

The conductive pattern layers CPL may include the same material, e.g.,aluminum (Al), but they should not be limited thereto or thereby. Thatis, the conductive pattern layers CPL may include Cu or ITO.

The conductive pattern layers CPL may include the different materialsfrom each other. For instance, when the conductive pattern CP includestwo conductive pattern layers CPL, one conductive pattern layer CPL ofthe two conductive pattern layers CPL may include aluminum (Al) and theother conductive pattern layer CPL of the two conductive pattern layersCPL may include copper (Cu). In addition, when the conductive pattern CPincludes four conductive pattern layers CPL, the conductive pattern CPincludes a conductive pattern layer including aluminum (Al), aconductive pattern layer including copper (Cu), a conductive patternlayer including aluminum (Al), and a conductive pattern layer includingcopper (Cu), which are sequentially stacked one on another. Further,when the conductive pattern CP includes four conductive pattern layersCPL, the conductive pattern CP includes a conductive pattern layerincluding aluminum (Al), a conductive pattern layer including silver(Ag), a conductive pattern layer including aluminum (Al), and aconductive pattern layer including silver (Ag), which are sequentiallystacked one on another.

Referring to FIG. 2C, the conductive pattern CP includes a firstconductive pattern layer CPL1, a second conductive pattern layer CPL2,and a third conductive pattern layer CPL3. The second conductive patternlayer CPL2 is disposed on the first conductive pattern layer CPL1. Thethird conductive pattern layer CPL3 is disposed on the second conductivepattern layer CPL2.

The first, second, and third conductive pattern layers CPL1, CPL2, andCPL3 may include the same material. For instance, each of the conductivepattern layers CPL may include aluminum (Al), but it should not belimited thereto or thereby. For example, each of the conductive patternlayers CPL may include copper (Cu). The first, second, and thirdconductive pattern layers CPL1, CPL2, and CPL3 may have the samethickness, or at least one conductive pattern layer of the first,second, and third conductive pattern layers CPL1, CPL2, and CPL3 mayhave a different thickness from that of the other conductive patternlayers.

For instance, the conductive pattern CP may include the first conductivepattern layer CPL1 including aluminum (Al), the second conductivepattern layer CPL2 disposed on the first conductive pattern layer CPL1and including copper (Cu), and the third conductive pattern layer CPL3disposed on the second conductive pattern layer CPL2 and includingaluminum (Al). In this case, the thicknesses of the first, second, andthird conductive pattern layers CPL1, CPL2, and CPL3 may be about 100nm, about 100 nm, and about 100 nm, respectively.

For instance, the conductive pattern CP may include the first conductivepattern layer CPL1 including titanium (Ti), the second conductivepattern layer CPL2 disposed on the first conductive pattern layer CPL1and including copper (Cu), and the third conductive pattern layer CPL3disposed on the second conductive pattern layer CPL2 and includingaluminum (Al). In this case, the thicknesses of the first, second, andthird conductive pattern layers CPL1, CPL2, and CPL3 may be about 200nm, about 150 nm, and about 150 nm, respectively.

Referring to FIG. 2D, the conductive pattern CP may include a firstconductive pattern layer CPL1, a first air layer AIL1, a secondconductive pattern layer CPL2, a second air layer AIL2, and a thirdconductive pattern layer CPL3.

The first air layer AIL1 is disposed on the first conductive patternlayer CPL1. The second conductive pattern layer CPL2 is disposed on thefirst air layer AIL1. The second air layer AIL2 is disposed on thesecond conductive pattern CPL2. The third conductive pattern layer CPL3is disposed on the second air layer AIL2.

Each of the first and third conductive pattern layers CPL1 and CPL3 hasa thickness equal to or greater than about 10 nm and equal to or lessthan about 150 nm, and the second conductive pattern layer CPL2 has athickness equal to or greater than about 5 nm and less than about 10 nm.

A region of the first conductive pattern layer CPL1, which makes contactwith the first air layer AIL1, may be oxidized. Regions of the secondconductive pattern layer CPL2, which respectively make contact with thefirst air layer AIL1 and the second air layer AIL2, may be oxidized. Aregion of the third conductive pattern layer CPL3, which makes contactwith the second air layer AIL2, may be oxidized.

For instance, the conductive pattern CP may include the first conductivepattern CPL1 including aluminum (Al), the second conductive patternlayer CPL2 disposed on the first conductive pattern layer CPL1 andincluding titanium (Ti), and the third conductive pattern

CPL3 disposed on the second conductive pattern layer CPL2 and includingaluminum (Al). In this case, the thicknesses of the first, second, andthird conductive pattern layers CPL1, CPL2, and CPL3 may be about 150nm, about 5 nm, and about 150 nm, respectively.

The first conductive pattern layer CPL1 in the region making contactwith the first air layer AIL1 is oxidized and exists in aluminum oxide,and the second conductive pattern layer CPL2 in the region makingcontact with the first air layer AIL1 and the second conductive patternlayer CPL2 in the region making contact with the second air layer AIL2are oxidized and exist in titanium oxide, and the third conductivepattern layer CPL3 in the region making contact with the second airlayer AIL2 is oxidized and exists in aluminum oxide.

FIG. 3A is a perspective view showing a flexible display deviceaccording to an exemplary embodiment of the present disclosure, FIG. 3Bis a cross-sectional view showing a wiring included in a flexibledisplay device according to an exemplary embodiment of the presentdisclosure, and FIG. 3C is a cross-sectional view showing an electrodeincluded in a flexible display device according to an exemplaryembodiment of the present disclosure.

Referring to FIGS. 1A to 1C and 3A, the conductive pattern CP includes awiring WI and an electrode EL. The wiring WI may be included in a touchscreen panel TSP (refer to FIG. 5A) and a flexible display panel DP(refer to FIG. 5A).

The wiring WI is disposed on the flexible substrate FB. At least aportion of the wiring WI is disposed on the bending part BF. Forinstance, the wring WI may be disposed on the bending part BF and maynot be disposed on the non-bending part NBF. As another way, the wringWI may be disposed on the bending part BF and the non-bending part NBF.

The wiring WI has a grain size of about 10 nm to about 100 nm. When thegrain is size of the wiring WI is less than about 10 nm, a resistance ofthe wiring WI increases, and thus, power consumption required to drivethe flexible display device 10 increases. When the grain size of thewiring WI is greater than about 100 nm, it is difficult to secureflexibility of the bending of the wiring WI since the grain size isexcessively large. As a result, a crack or a disconnection occurs in thewiring WI, and reliability of the flexible display device 10 is reduced.

Referring to FIGS. 1A to 1C, 3A, and 3B, the wiring WI includes aplurality of wiring layers WIL. The number of the wiring layers WILincluded in the wiring WI is two, three, four, five, or six, but itshould not be limited thereto or thereby. That is, the wiring WI mayinclude seven or more wiring layers WIL. The grains arranged indifferent wiring layers WIL are not connected to each other. That is,the grains are included in each of the wiring layers WIL.

Each of the wiring layers WIL has a grain size of about 10 nm to about100 nm. When the grain size of the wiring layers WIL is less than about10 nm, a resistance of the wiring layers WIL increases, and thus, powerconsumption required to drive the flexible display device 10 increases.When the grain size of the wiring layers WIL is greater than about 100nm, it is difficult to secure flexibility of the bending of the wiringlayers WIL since the grain size is excessively large. As a result, acrack or a disconnection occurs in the wiring layers WIL, andreliability of the flexible display device 10 is reduced.

Each of the wiring layers WIL has a thickness of about 10 nm to abut 150nm. When the thickness of each of the wiring layers WIL is less thanabout 10 nm, the number of the interfaces of the wiring layers WILincreases even though the overall thickness of the wiring WI is notincreased, and thus, the resistance of the wiring WI increases.Accordingly, power consumption required to drive the flexible displaydevice 10 increases. In addition, the reliability of the wiring layersWIL may be reduced when each wiring layer WIL is manufactured orprovided. When the thickness of each of the wiring layers WIL exceedsabout 150 nm, it is difficult to secure flexibility of the wiring layersWIL when the wiring layers WIL are bent. As a result, a crack or adisconnection occurs in the wiring layers WIL. and reliability of thewiring layers WIL is reduced.

Each of the wiring layers WIL includes at least one of a metal, a metalalloy, and a transparent conductive oxide, but it should not be limitedthereto or thereby.

The metal may include, but not limited to, at least one of Al, Cu, Ti,Mo, Ag, Mg, Pt, Pd, Au, Ni, Nd, Ir, and Cr.

The transparent conductive oxide may include, but not limited to, atleast one of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide(ZnO), and indium tin zinc oxide (ITZO).

Referring to FIGS. 1A to 1C, 3A, and 3C, the electrode EL is disposed onthe flexible substrate FB. At least a portion of the electrode EL isdisposed on the bending part BF. For instance, the electrode EL may bedisposed on the bending part BF and may not be disposed on thenon-bending part NBF. As another way, the electrode EL may be disposedon the bending part BF and the non-bending part NBF.

The electrode EL is electrically connected to the wiring WI. Theelectrode EL may be spaced apart from the wiring WI, but it should notbe limited thereto or thereby. That is, the electrode EL may beintegrally formed with the wiring WI.

The electrode EL and the wiring WI may be disposed on the same layer,but they should not be limited thereto or thereby. That is, theelectrode EL and the wiring WI may be disposed on different layers fromeach other. Although not shown in figures, an intermediate layer may bedisposed between the wiring WI and the electrode EL.

The electrode EL has a grain size of about 10 nm to about 100 nm. Whenthe grain size of the electrode EL is less than about 10 nm, aresistance of the electrode EL increases, and thus, power consumptionrequired to drive the flexible display device 10 increases. When thegrain size of the electrode EL is greater than about 100 nm, it isdifficult to secure flexibility of the bending of the electrode EL sincethe grain size is excessively large. As a result, a crack or adisconnection occurs in the electrode EL, and reliability of theflexible display device 10 is reduced.

The electrode EL includes a plurality of electrode layers ELL. Thenumber of the electrode layers ELL included in the electrode EL is two,three, four, five, or six, but it should not be limited thereto orthereby. That is, the electrode EL may include seven or more electrodelayers ELL. The grains arranged in different electrode layers ELL arenot connected to each other. That is, the grains are included in each ofthe electrode layers ELL.

Each of the electrode layers ELL has a grain size of about 10 nm toabout 100 nm. When the grain size of the electrode layers ELL is lessthan about 10 nm, a resistance of the electrode layers ELL increasessince the number of the interfaces of the electrode layers ELL increaseseven though the overall thickness of the electrode EL is not increased.Thus, power consumption required to drive the flexible display device 10increases. In addition, the reliability of the electrode layers ELL maybe reduced when each electrode layer ELL is manufactured or provided.When the thickness of each of the electrode layers ELL is greater thanabout 150 nm, it is difficult to secure flexibility of the electrodelayers ELL when the electrode layers ELL are bent. As a result, a crackor a disconnection occurs in the electrode layers ELL, and reliabilityof the electrode layers ELL is reduced.

Each of the electrode layers ELL includes at least one of a metal, ametal alloy, and a transparent conductive oxide, but it should not belimited thereto or thereby.

The metal may include, but not limited to, at least one of Al, Cu, Ti,Mo, Ag, Mg, Pt, Pd, Au, Ni, Nd, Ir, and Cr.

The transparent conductive oxide may include, but not limited to, atleast one of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide(ZnO), and indium tin zinc oxide (ITZO).

FIG. 4A is a perspective view showing a flexible display deviceaccording to an exemplary embodiment of the present disclosure, FIG. 4Bis a cross-sectional view taken along a line II-II′ of FIG. 4A, FIG. 4Cis a cross-sectional view showing a first wiring included in a flexibledisplay device according to an exemplary embodiment of the presentdisclosure, and FIG. 4D is a cross-sectional view showing a secondwiring included in a flexible display device according to an exemplaryembodiment of the present disclosure.

Referring to FIGS. 1A to 1C, 4A, and 4B, the wiring WI includes thefirst wiring WI1 and the second wiring WI2. An insulating layer IL isdisposed between the first and second wirings WI1 and WI2. The firstwiring WI1 is disposed between the flexible substrate and the insulatinglayer IL and the second wiring WI2 is disposed on the insulating layerIL. The insulating layer IL may include, but not limited to, an organicinsulating material or an inorganic insulating material.

Referring to FIG. 4C, the first wiring WI1 includes a plurality of firstwiring layers WIL1 . The number of the first wiring layers WIL1 includedin the first wiring WI1 is two, three, four, five, or six, but it shouldnot be limited thereto or thereby. That is, the first wiring WI mayinclude seven or more first wiring layers WIL1. The second wiring WI2includes two, three, four, five, or six second wiring layers WIL2, butit should not be limited thereto or thereby. That is, the second wiringWI2 may include seven or more second wiring layers WIL2.

Referring to FIGS. 1A to 1C and FIGS. 4A to 4D, each of the first andsecond wiring layers WIL1 and WIL2 has a grain size of about 10 nm toabout 100 nm. When the grain size of the first and second wiring layersWIL1 and WIL2 is less than about 10 nm, a resistance of the first andsecond wiring layers WIL1 and WIL2 increases, and thus, powerconsumption required to drive the flexible display device 10 increases.When the grain size of the first and second wiring layers WIL1 and WIL2is greater about 100 nm, it is difficult to secure flexibility of thebending of the first and second wiring layers WIL1 and WIL2 since thegrain size is excessively large. As a result, a crack or a disconnectionoccurs in the first and second wiring layers WIL1 and WIL2, andreliability of the flexible display device 10 is reduced.

Each of the first and second wiring layers WIL1 and WIL2 has a thicknessof about 10 nm to abut 150 nm. When the thickness of each of the firstand second wiring layers WIL1 and WIL2 is less than about 10 nm, thenumber of the interfaces of the first wiring layers WIL1 increases eventhough the overall thickness of the first wiring WI1 is not increasedand the number of the interfaces of the second wiring layers WIL2increases even though the overall thickness of the second wiring WI2 isnot increased. Thus, the resistance of the first wiring WI1 increases.Accordingly, power consumption required to drive the flexible displaydevice 10 increases. In addition, the reliability of the first andsecond wiring layers WIL1 and WIL2 may be reduced when each of the firstand second wiring layers WIL1 and WIL2 is manufactured or provided. Whenthe thickness of each of the first and second wiring layers WIL1 andWIL2 is is greater than about 150 nm, it is difficult to secureflexibility of the first and second wiring layers

WIL1 and WIL2 when the first wiring WI1 is bent. As a result, a crack ora disconnection occurs in the first and second wiring layers WIL1 andWIL2, and the reliability of the first and second wiring layers WIL1 andWIL2 is reduced.

Each of the first and second wiring layers WIL1 and WIL2 includes atleast one of a metal, a metal alloy, and a transparent conductive oxide,but it should not be limited thereto or thereby.

The metal may include, but not limited to, at least one of Al, Cu, Ti,Mo, Ag, Mg, Pt, Pd, Au, Ni, Nd, Ir, and Cr.

The transparent conductive oxide may include, but not limited to, atleast one of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide(ZnO), and indium tin zinc oxide (ITZO).

FIGS. 5A, 5B, and 5C are perspective views showing a flexible displaydevice according to an exemplary embodiment of the present disclosure.

Referring to FIGS. 5A to 5C, the flexible display device 10 is operatedin the first mode or the second mode. The flexible display device 10includes the touch screen panel TSP and the flexible display panel DP.The touch screen panel TSP is disposed on the flexible display panel DPin the first direction DR1.

The touch screen panel TSP includes a touch bending part BF2 and a touchnon-bending part NBF2. The touch bending part BF2 is bent in the firstmode with respect to a bending axis BX1 extending in the seconddirection DR2, and is unbent in the second mode. The touch bending partBF2 is connected to the touch non-bending part NBF2. The touchnon-bending part NBF2 is not bent in the first and second modes.

The flexible display panel DP includes a panel bending part BF1 and apanel non-bending part NBF1. The panel bending part BF1 is bent in thefirst mode with respect to the bending axis BX1 extending in the seconddirection DR2 and is unbent in the second mode. The panel bending partBF1 is connected to the panel non-bending part NBF1. The panelnon-bending part NBF1 is not bent in the first and second modes.

Referring to FIGS. 5A and 5C, at least a portion of the touch screenpanel TSP and the flexible display panel DP is bent in the first mode.Referring to FIG. 5B, the touch bending part BF2 of the touch screenpanel TSP and the panel bending part BF1 of the flexible display panelDP are unbent in the second mode.

The first mode includes a first bending mode and a second bending mode.Referring to FIG. 5A, the flexible display device 10 is bent in onedirection with respect to the bending axis BX1 in the first bendingmode. The flexible display device 10 is inwardly bent in the firstbending mode. When the flexible display device 10 is in theinner-bending state, a distance between portions facing each other ofthe touch screen panel TSP after the touch screen panel TSP is bent isshorter than a distance between portions facing each other of theflexible display panel DP after the flexible display panel DP is bent.In the inner-bending state, a surface of the touch bending part BF2 ofthe touch screen panel TSP has a third radius of curvature R3. The thirdradius of curvature R3 is in a range from about lnm to about 10 nm.

Referring to FIG. 5C, the flexible display device 10 is bent in adirection opposite to the one direction of FIG. 5A with respect to thebending axis BX1 in the second bending mode. The flexible display device10 is outwardly bent in the second bending mode. When the flexibledisplay device 10 is in the outer-bending state, a distance betweenportions facing each other of the flexible display panel DP after theflexible display panel DP is bent is less than a distance betweenportions facing each other of the touch screen panel TSP after the touchscreen panel TSP is bent. In the outer-bending state, a surface of thepanel bending part BF1 of the flexible display panel DP has a fourthradius of curvature R4. The fourth radius of curvature R4 is in a rangefrom about lnm to about 10 nm.

Referring to FIGS. 1A to 1C and 5A to 5C, at least one of the flexibledisplay panel DP and the touch screen panel TSP includes a conductivepattern CP having a grain size of about 10 nm to about 100 nm. Theconductive pattern CP is included in at least one of the panel bendingpart BF1 and the touch bending part BF2. The conductive pattern CPincludes the conductive pattern layers CPL (refer to FIG. 2B) eachhaving the grain size of about 10 nm to about 100 nm.

FIG. 6A is a circuit diagram showing one of the pixels included in aflexible display panel according to an exemplary embodiment of thepresent disclosure, FIG. 6B is a plan view showing one pixel of pixelsincluded in a flexible display panel according to an exemplaryembodiment of the present disclosure, and FIG. 6C is a cross-sectionalview taken along a line of FIG. 6B.

Hereinafter, an organic light emitting display panel will be describedas the flexible display panel DP, but the flexible display panel DPshould not be limited to the organic light emitting display panel. Thatis, the flexible display panel DP may be a liquid crystal display panel,a plasma display panel, an electrophoretic display panel, amicroelectromechanical system display panel, or an electrowettingdisplay panel.

Referring to FIGS. 1A to 1C, 5A to 5C, 6A, and 6B, the flexible displaypanel DP includes the conductive pattern CP disposed on the flexiblesubstrate FB. At least a portion of the conductive pattern CP isincluded in the panel bending part BF1. The conductive pattern CP may beincluded in the panel bending part BF1 and may not be included in thepanel non-bending part NBF1. The conductive pattern CP may be includedin each of the panel bending part BF1 and the panel non-bending partNBF1. The conductive pattern CP has a grain size of about 10 nm to about100 nm. The conductive pattern CP includes the conductive pattern layersCPL (refer to FIG. 2B) each having the grain size of about 10 nm toabout 100 nm.

The conductive pattern CP includes gate lines GL, data lines DL, drivingvoltage lines DVL, a switching thin film transistor TFT1, a driving thinfilm transistor TFT2, a capacitor Cst, a first semiconductor patternSM1, a second semiconductor pattern SM2, a first electrode EL1, and asecond electrode EL2. The switching thin film transistor TFT1 includes afirst gate electrode GE1, a first source electrode SE1, and a firstdrain electrode DE1. The driving thin film transistor TFT2 includes asecond gate electrode GE2, a second source electrode SE2, and a seconddrain electrode DE2. The capacitor Cst includes a first common electrodeCE1 and a second common electrode CE2.

Referring to FIGS. 6A and 6B, each pixel PX is connected to a line partincluding the gate lines GL, the data lines DL, and the driving voltagelines DVL. Each pixel PX includes the thin film transistors TFT1 andTFT2 connected to the line part and an organic light emitting elementOEL connected to the thin film transistors TFT1 and TFT2, and thecapacitor Cst.

In the present exemplary embodiment, one pixel is connected to one gateline, one data line, and one driving voltage line, but it should not belimited thereto or thereby. That is, a plurality of pixels may beconnected to one gate line, one data line, and one driving voltage line.In addition, one pixel may be connected to at least one gate line, atleast one data line, and at least one driving voltage line.

The gate lines GL extend in a third direction DR3. The data lines DLextend in a fourth direction DR4 to cross the gate lines GL. The drivingvoltage lines DVL extend in the fourth direction DR4. The gate lines GLapply scan signals to the thin film transistors TFT1 and TFT2, the datalines DL apply data signals to the thin film transistors TFT1 and TFT2,and the driving voltage lines DVL apply driving voltages to the thinfilm transistors TFT1 and TFT2.

At least one of the gate lines GL, the data lines DL, and the drivingvoltage lines DVL may have a grain size of about 10 nm to about 100 nm.At least one of the gate lines GL, the data lines DL, and the drivingvoltage lines DVL may include a plurality of layers, each having thegrain size of about 10 nm to about 100 nm. Each of the layers includedin at least one of the gate lines GL, the data lines DL, and the drivingvoltage lines DVL may have a thickness of about 10 nm to about 150 nm.

Each of the pixels PX emits a light with a specific color, e.g., a redlight, a green light, or a blue light, but the color of the light shouldnot be limited thereto or thereby. For instance, each pixel may emit awhite color, a cyan light, a magenta light, or a yellow light.

The thin film transistors TFT1 and TFT2 includes the driving thin filmtransistor TFT2 to control the organic light emitting element OEL andthe switching thin film transistor TFT1 to switch the driving thin filmtransistor TFT2. In the present exemplary embodiment, each pixel PXincludes two thin film transistors TFT1 and TFT2, but it should not belimited thereto or thereby. That is, each pixel PX may include one thinfilm transistor and a capacitor or may include three or more thin filmtransistors and two or more capacitors.

At least one of the switching thin film transistor TFT1, the drivingthin film transistor TFT2, and the capacitor Cst may have a grain sizeof about 10 nm to about 100 nm. At least one of the switching thin filmtransistor TFT1, the driving thin film transistor TFT2, and thecapacitor Cst may include a plurality of layers, each having the grainsize of about 10 nm to about 100 nm. Each of the layers included in atleast one of the switching thin film transistor TFT1, the driving thinfilm transistor TFT2, and the capacitor Cst may have a thickness ofabout 10 nm to about 150 nm.

The switching thin film transistor TFT1 includes the first gateelectrode GE1, the first source electrode SE1, and the first drainelectrode DEl. The first gate electrode GE1 is connected to the gatelines GL and the first source electrode SE1 is connected to the datalines DL. The first drain electrode DE1 is connected to a first commonelectrode CE1 through a fifth contact hole CH5. The switching thin filmtransistor TFT1 applies the data signal provided through the data linesDL to the driving thin film transistor TFT2 in response to the scansignal provided through the gate lines GL.

At least one of the first gate electrode GE1, the first source electrodeSE1, and the first drain electrode DE1 may have a grain size of about 10nm to about 100 nm. At least one of the first gate electrode GE1, thefirst source electrode SE1, and the first drain electrode DE1 mayinclude a plurality of layers, each having a grain size of about 10 nmto about 100 nm. Each of the layers included in at least one of thefirst gate electrode GE1, the first source electrode SE1, and the firstdrain electrode DE1 may have a thickness of about 10 nm to about 150 nm.

The driving thin film transistor TFT2 includes the second gate electrodeGE2, the second source electrode SE2, and the second drain electrodeDE2. The second gate electrode GE2 is connected to the first commonelectrode CE1. The second source electrode SE2 is connected to thedriving voltage lines DVL. The second drain electrode DE2 is connectedto the first electrode EL1 through a third contact hole CH3.

At least one of the second gate electrode GE2, the second sourceelectrode SE2, and the second drain electrode DE2 may have a grain sizeof about 10 nm to about 100 nm. At least one of the second gateelectrode GE2, the second source electrode SE2, and the second drainelectrode DE2 may include a plurality of layers, each having a grainsize of about 10 nm to about 100 nm. Each of the layers included in atleast one of the second gate electrode GE2, the second source electrodeSE2, and the second drain electrode DE2 may have a thickness of about 10nm to about 150 nm.

The first electrode EL1 is connected to the second drain electrode DE2of the driving thin film transistor TFT2. The second electrode isapplied with a common voltage and a light emitting layer EML emits thelight in response to an output signal from the driving thin filmtransistor TFT2 to display an image. The first and second electrodes EL1and EL2 will be described in detail later.

The capacitor Cst is connected between the second gate electrode GE2 andthe second source electrode SE2 of the driving thin film transistor TFT2and is charged with the data signal applied to the second gate electrodeGE2 of the driving thin film transistor TFT2. The capacitor Cst includesa first common electrode CE1 connected to the first drain electrode DE1through a sixth contact hole CH6 and a second common electrode CE2connected to the driving voltage lines DVL.

At least one of the first common electrode CE1 and the second commonelectrode CE2 may have a grain size of about 10 nm to about 100 nm. Atleast one of the first common electrode CE1 and the second commonelectrode CE2 may include a plurality of layers, each having the grainsize of about 10 nm to about 100 nm. Each of the layers included in atleast one of the first common electrode CE1 and the second commonelectrode CE2 may have a thickness of about 10 nm to about 150 nm.

Referring to FIGS. 6A to 6C, a first flexible substrate FB1 may include,but not limited to, a plastic material or an organic polymer, e.g.,polyethylene (PET), polyethylene naphthalate (PEN), polyimide, polyethersulfone, etc. The material for the first flexible substrate FB1 isselected in consideration of mechanical strength, thermal stability,transparency, surface smoothness, ease of handling, water repellency,etc. The first flexible substrate FB may be transparent.

A substrate buffer layer (not shown) may be disposed on the firstflexible substrate FB1. The substrate buffer layer prevents impuritiesfrom being diffused into the switching thin film transistor TFT1 and thedriving thin film transistor TFT2. The substrate buffer layer may beformed of silicon nitride (SiN_(x)), silicon oxide (SiO_(x)), or siliconoxynitride (SiO_(x)N_(y)) and omitted depending on material and processcondition of the first flexible substrate FB1.

A first semiconductor pattern SM1 and a second semiconductor pattern SM2are disposed on the first flexible substrate FB1. The first and secondsemiconductor patterns SM1 and SM2 are formed of a semiconductormaterial and operated as active layers of the switching thin filmtransistor TFT1 and the driving thin film transistor TFT2, respectively.Each of the first and second semiconductor patterns SM1 and SM2 includesa source part SA, a drain part DA, and a channel part CA disposedbetween the source part SA and the drain part DA. Each of the first andsecond semiconductor patterns SM1 and SM2 is formed of an inorganicsemiconductor or an organic semiconductor. The source part SA and thedrain part DA are doped with an n-type impurity or a p-type impurity.

At least one of the first semiconductor pattern SM1 and the secondsemiconductor pattern SM2 may have a grain size of about 10 nm to about100 nm. At least one of the first semiconductor pattern SM1 and thesecond semiconductor pattern SM2 may include a plurality of layers, eachhaving a grain size of about 10 nm to about 100 nm. Each of the layersincluded in at least one of the first semiconductor pattern SM1 and thesecond semiconductor pattern SM2 may have a thickness of about 10 nm toabout 150 nm.

A gate insulating layer GI is disposed on the first and secondsemiconductor patterns SM1 and SM2. The gate insulating layer GI coversthe first and second semiconductor patterns SM1 and SM2. The gateinsulating layer GI includes an organic insulating material or aninorganic insulating material.

The first and second gate electrodes GE1 and GE2 are disposed on thegate insulating layer GI. The first and second gate electrodes GE1 andGE2 are disposed to respectively cover portions corresponding to thedrain parts DA of the first and second semiconductor patterns SM1 andSM2.

A first insulating layer IL1 is disposed on the first and second gateelectrodes GE1 and GE2. The first insulating layer IL1 covers the firstand second gate electrodes GE1 and GE2. The first insulating layer IL1includes an organic insulating material or an inorganic insulatingmaterial.

The first source electrode SE1, the first drain electrode DE1, thesecond source electrode SE2, and the second drain electrode DE2 aredisposed on the first insulating layer IL1. The second drain electrodeDE2 makes contact with the drain part DA of the second semiconductorpattern SM2 through a first contact hole CH1 formed through the gateinsulating layer GI and the first insulating layer ILL and the secondsource electrode SE2 makes contact with the source part SA of the secondsemiconductor pattern SM2 through a second contact hole CH2 formedthrough the gate insulating layer GI and the first insulating layer IL1.The first source electrode SE1 makes contact with the source part (notshown) of the first semiconductor pattern SM1 through a fourth contacthole CH4 formed through the gate insulating layer GI and the firstinsulating layer IL1 and the first drain electrode DE1 makes contactwith the drain part (not shown) of the first semiconductor pattern SM1through a fifth contact hole CH5 formed through the gate insulatinglayer GI and the first insulating layer IL1.

A passivation layer PL is disposed on the first source electrode SE1,the first drain electrode DE1, the second source electrode SE2, and thedrain electrode DE2. The passivation layer PL serves as a protectivelayer to protect the switching thin film transistor TFT1 and the drivingthin film transistor TFT2 or as a planarization layer to planarize anupper surface of the switching thin film transistor TFT1 and the drivingthin film transistor TFT2.

The first electrode EL1 is disposed on the passivation layer PL. Thefirst electrode EL1 may be a positive electrode. The first electrode EL1is connected to the second drain electrode DE2 of the driving thin filmtransistor TR2 through a third contact hole CH3 formed through thepassivation layer PL.

A pixel definition layer PDL is disposed on the passivation layer PL todivide the light emitting layer EML to correspond to each of the pixelPX. The pixel definition layer PDL exposes an upper surface of the firstelectrode EL1 and is protruded from the first flexible substrate FB1.The pixel definition layer PDL may include, but is not limited to,metal-fluoride ionic compounds, e.g., LiF, BaF₂, CsF. The metal-fluorideionic compounds may have an insulating property when the metal-fluorideionic compounds have a predetermined thickness. The pixel definitionlayer PDL has a thickness of about 10 nm to abut 100 nm. The pixeldefinition layer PDL will be described in detail later.

The organic light emitting element OEL is provided in the areasurrounding by the pixel definition layer PDL. The organic lightemitting layer OEL includes the first electrode EL1, a hole transportregion HTR, the light emitting layer EML, an electron transport regionETR, and the second electrode EL2.

The first electrode EL1 has conductivity. The first electrode EL1 may bea pixel electrode or a positive electrode. The first electrode EL1 has agrain size of about 10 nm to about 100 nm. The first electrode EL1 mayinclude a plurality of layers, each having a grain size of about 10 nmto about 100 nm. Each of the layers included in the first electrode EL1may have a thickness of about 10 nm to about 150 nm.

The first electrode EL1 may be a transmissive electrode, a transflectiveelectrode, or a reflective electrode. When the first electrode EL1 isthe transmissive electrode, the first electrode EL1 includes atransparent metal oxide, e.g., indium tin oxide (ITO), indium zinc oxide(IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc. When thefirst electrode EL1 is the transflective electrode or the reflectiveelectrode, the first electrode EL1 includes at least one of Al, Cu, Ti,Mo, Ag, Mg, Pt, Pd, Au, Ni, Nd, Ir, and Cr.

An organic layer is disposed on the first electrode EL1. The organiclayer includes the light emitting layer EML. The organic layer mayfurther include the hole transport region HTR and the electrodetransport region ETR.

The hole transport region HTR is disposed on the first electrode EL1.The hole transport region HTR includes at least one of a hole injectionlayer, a hole transport layer, a buffer layer, and an electron blocklayer.

The hole transport region HTR has a single-layer structure of a singlematerial, a single-layer structure of different materials, or amulti-layer structure of plural layers of different materials.

For instance, the hole transport region HTR may have a structure inwhich single is layers formed of different materials from each other arestacked one on another or a structure of the hole injection layer/thehole transport layer, the hole injection layer/the hole transportlayer/the buffer layer, the hole injection layer/the buffer layer, thehole transport layer/the buffer layer, or the hole injection layer/thehole transport layer/the electron block layer.

The hole transport region HTR may be formed using various methods, e.g.,a vacuum deposition method, a spin coating method, a casting method, aLangmuir-Blodgett method, an inkjet printing method, a laser printingmethod, a laser induced thermal image (LITI) method, etc.

When the hole transport region HTR includes the hole injection layer,the hole transport region HTR may include, but not limited to, aphthalocyanine compound such as copper phthalocyanine, DNTPD(N,N′-diphenyl-N,N′-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4′-diamine),m-MTDATA(4,4′,4″-tris(3-methylphenylphenylamino)triphenylamine),TDATA(4,4′4″-Tris(N,N-diphenylamino)triphenylamine),2TNATA(4,4′,4″-tri{N,-(2-naphthyl)-N-phenylamino}-triphenylamine),PEDOT/PSS(Poly(3,4-ethylenedioxythiophene)/Poly(4-styrenesulfonate),PANI/DBSA(Polyaniline/Dodecylbenzenesulfonic acid),PANI/CSA(Polyaniline/Camphor sulfonicacid),PANI/PSS((Polyaniline)/Poly(4-styrenesulfonate), etc.

When the hole transport region HTR includes the hole transport layer,the hole transport region HTR may include, but not limited to,carbazole-based derivatives, e.g., n-phenyl carbazole, polyvinylcarbazole, etc., fluorine-based derivatives. triphenylamine-basedderivatives, e.g.TPD(N,N′-bis(3-methylphenyl)-N,N′-diphenyl[1,1-biphenyl]-4,4′-diamine),TCTA(4,4′,4″-tris(N-carbazolyl)triphenylamine), etc.,NPB(N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine),TAPC(4,4′-Cyclohexylidene bis[N,N-bis(4-methylphenyl)benzenamine]), etc.

The hole transport region HTR may further include an electric chargegenerating material. The electric charge generating material may beuniformly or non-uniformly distributed in the hole transport region HTR.The electric charge generating material may be, but not limited to, ap-dopant. The p-dopant may be one of a quinone derivative, a metal oxidematerial, and a compound containing a cyano group, but it should not belimited thereto or thereby. For instance, the p-dopant may include thequinone derivatives, such as TCNQ(Tetracyanoquinodimethane),F4-TCNQ(2,3,5,6-tetrafluoro-tetracyanoquinodimethane), etc., or themetal oxide material, such as a tungsten oxide material, a molybdenumoxide material, etc., but it should not be limited thereto or thereby.

The light emitting layer EML is disposed on the hole transport regionHTR. The light emitting layer EML includes a light emitting materialwith red, green, and blue colors and includes a fluorescence material ora phosphorescent material. In addition, the light emitting layer EMLincludes a host and a dopant.

As the host, for example, Alq3(tris(8-hydroxyquinolino)aluminum),CBP(4,4′-bis(N-carbazolyl)-1,1′-biphenyl), PVK(poly(n-vinylcabazole),ADN(9,10-di(naphthalene-2-yl)anthracene),TCTA(4,4′,4″-Tris(carbazol-9-yl)-triphenylamine),TPBi(1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene),TBADN(3-tert-butyl-9,10-di(naphth-2-yl)anthracene),DSA(distyrylarylene),CDBP(4,4′-bis(9-carbazolyl)-2,2″-dimethyl-biphenyl),MADN(2-Methyl-9,10-bis(naphthalen-2-yl)anthracene) may be used, however,it should not be limited thereto or thereby.

When the light emitting layer EML emits light having a red color, thelight emitting layer EML, for example, may include the fluorescentmaterial includingPBD:Eu(DBM)3(Phen)(tris(dibenzoylmethanato)phenanthoroline europium) orperylene. When the light emitting layer EML emits light having a redcolor, the light emitting layer EML, the host included in the lightemitting layer EML may be selected from a metal complex, such asPIQIr(acac)(bis(1-phenylisoquinoline)acetylacetonate iridium),PQIr(acac)(bis(1-phenylquinoline)acetylacetonate iridium),PQIr(tris(1-phenylquinoline)iridium), PtOEP(octaethylporphyrinplatinum), etc., or organometallic complex.

When the light emitting layer EML emits light having a green color, thelight emitting layer EML, for example, may include the fluorescentmaterial including Alq3(tris(8-hydroxyquinolino)aluminum). When thelight emitting layer EML emits light having a green color, the lightemitting layer EML, the host included in the light emitting layer EMLmay be selected from a metal complex, such asIr(ppy)3(fac-tris(2-phenylpyridine)iridium), or organometallic complex.

When the light emitting layer EML emits light having a blue color, thelight emitting layer EML, for example, may include the fluorescentmaterial including any one selected from the groups consisting ofspiro-DPVBi, spiro-6P, DSB(distyryl-benzene), DSA(distyryl-arylene),PFO(Polyfluorene)-based polymer, and PPV(poly(p-phenylenevinylene)-based polymer. When the light emitting layer EML emits lighthaving a blue color, the light emitting layer EML, the host included inthe light emitting layer EML may be selected from a metal complex, suchas (4,6-F2ppy)2Irpic, or organometallic complex. The light emittinglayer EML will be described in detail later.

The electron transport region ETR is disposed on the light emittinglayer EML. The electron transport region ETR includes at least one of ahole block layer, an electron transport layer, and an electron injectionlayer, but it should not be limited thereto or thereby.

When the electron transport region ETR includes the electron transportlayer, the electron transport region ETR includesAlq3(Tris(8-hydroxyquinolinato)aluminum),TPBi(1,3,5-Tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl),BCP(2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline),Bphen(4,7-Diphenyl-1,10-phenanthroline),TAZ(3-(4-Biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole),NTAZ(4-(Naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole),tBu-PBD(2-(4-Biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole),BAlq(Bis(2-methyl-8-quinolinolato-N1,O8)-(1,1′-Biphenyl-4-olato)aluminum),Bebq2(berylliumbis(benzoquinolin-10-olate),ADN(9,10-di(naphthalene-2-yl)anthracene), or a compound thereof. Theelectron transport layer has a thickness of about 100 angstroms to about1000 angstroms, and may have a thickness of about 150 angstroms to about500 angstroms. When the thickness of the electron transport layer is inthe above-mentioned range of about 100 angstroms to about 1000angstroms, satisfactory electron transport property may be securedwithout increasing the driving voltage.

When the electron transport region ETR includes the electron injectionlayer, the electron transport region ETR includes a lanthanide-basedmetal, e.g., LiF, LiQ (Lithium quinolate), Li₂O, BaO, NaCl, CsF, Yb,etc., or a metal halide, e.g., RbCl, RbI, etc., but it should not belimited thereto or thereby. The electron transport layer may include amixture of an electron transport material and an organo metal salt withinsulating property. The organo metal salt has an energy band gap ofabout 4 eV or more. In detail, the organo metal salt may include metalacetate, metal benzoate, metal acetoacetate, metal acetylacetonate, ormetal stearate. The electron injection layer has a thickness of about 1angstroms to about 100 angstroms, and may have a thickness of about 3angstroms to about 90 angstroms. When the thickness of the electroninjection layer is in the above-mentioned range of about 1 angstroms toabout 100 angstroms, satisfactory electron injection property may besecured without increasing the driving voltage.

As described above, the electron transport region ETR includes the holeblock layer. The hole block layer include at least one ofBCP(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) andBphen(4,7-diphenyl-1,10-phenanthroline), but it should not be limitedthereto or thereby.

The second electrode EL2 is disposed on the electron transport regionETR. The second EL2 may be a common electrode or a negative electrode.The second electrode EL2 has a grain size of about 10 nm to about 100nm. The second electrode EL2 may include a plurality of layers, eachhaving a grain size of about 10 nm to about 100 nm. Each of the layersincluded in the first electrode EL1 may have a thickness of about 10 nmto about 150 nm.

The second electrode EL2 may be a transmissive electrode, atransflective electrode, or a reflective electrode. When the secondelectrode EL2 is the transmissive electrode, the second electrode EL2includes Li, Ca, LiF/Ca, LiF/Al, Al, Mg, BaF, Ba, Ag, a compoundthereof, or a mixture thereof, e.g., a mixture of Ag and Mg.

The second electrode EL2 may include an auxiliary electrode. Theauxiliary electrode includes a layer obtained by depositing the materialto face the light emitting layer EML and a transparent metal oxidedisposed on the layer, such as indium tin oxide, indium zinc oxide, zincoxide, indium tin zinc oxide, Mo, Ti, etc.

When the second electrode EL2 is the transflective electrode or thereflective electrode, the second electrode EL2 includes Ag, Mg, Cu, Al,Pt, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/Ca, LiF/Al, Mo, Ti, a compoundthereof, or a mixture thereof, e.g., a mixture of Ag and Mg. Inaddition, the second electrode EL2 has a multi-layer structure of areflective layer or a transflective layer formed of the above-mentionedmaterial and a transparent conductive layer formed of indium tin oxide,indium zinc oxide, zinc oxide, or indium tin zinc oxide.

When the organic light emitting element OEL is a front surface lightemitting type, the first electrode EL1 is the reflective electrode andthe second electrode EL2 is the transmissive or transflective electrode.When the organic light emitting element OEL is a rear surface lightemitting type, the first electrode EL1 is the transmissive ortransflective electrode and the second electrode EL2 is the reflectiveelectrode.

When voltages are respectively applied to the first and secondelectrodes EL1 and EL2, holes injected from the first electrode EL1 moveto the light emitting layer EML through the hole transport region HTRand electrons injected from the second electrode EL2 move to the lightemitting layer EML through the electron transport region ETR. The holesand electrons are recombined in the light emitting layer EML to generateexcitons, and the organic light emitting element OEL emits the light bythe excitons that return to a ground state from an excited state.

A sealing layer SL is disposed on the second electrode EL2. The sealinglayer SL covers the second electrode EL2. The sealing layer SL includesat least one of an organic layer and an inorganic layer. The sealinglayer SL is a thin sealing layer. The sealing layer SL protects theorganic light emitting element OEL.

FIG. 7A is a cross-sectional view showing a flexible display deviceaccording to an exemplary embodiment of the present disclosure and FIG.7B is a plan view showing a touch screen panel included in a flexibledisplay device according to an exemplary embodiment of the presentdisclosure.

FIG. 8A is a plan view showing a flexible display device according to anexemplary embodiment of the present disclosure and FIG. 8B is a planview showing a touch screen panel included in a flexible display deviceaccording to an exemplary embodiment of the present disclosure.

Referring to FIGS. 7A, 7B, 8A, and 8B, the touch screen panel TSP isdisposed on the flexible display panel DP. The touch screen panel TSPmay be disposed on the sealing layer SL (refer to FIG. 6C). The touchscreen panel TSP recognizes a user's direct touch, a user's indirecttouch, an object's direct touch, or an object's indirect touch. The termof “indirect touch” used herein means that the touch screen panel TSPrecognizes the touches even though the touch screen panel TSP is notactually touched by the user or object since the user or object isspaced apart from the touch screen panel TSP by a distance, in which thetouch screen panel TSP recognizes the touch of the user or object.

When the direct or indirect touch occurs, a variation in electrostaticcapacitance occurs between first sensing electrodes Tx and secondsensing electrodes Rx included in a sensing electrode TE. A sensingsignal applied to the first sensing electrodes Tx is delayed due to thevariation of the electrostatic capacitance and then applied to thesecond sensing electrodes Rx. The touch screen panel TSP generates atouch coordinate from the delay value of the sensing signal.

In the present exemplary embodiment, the touch screen panel TSP isoperated in an electrostatic capacitive mode, but it should not belimited thereto or thereby. That is, the touch screen panel TSP may beoperated in a resistive film mode, a self cap mode, or a mutual capmode.

Referring to FIGS. 1A to 1C, FIGS. 5A to 5C, and FIGS. 7A, 7B, 8A, and8B, at least the portion of the conductive pattern CP is included in thetouch bending part BF2. The conductive pattern CP may be included in thetouch bending part BF2 and may not be included in the touch non-bendingpart NBF2. The conductive pattern CP may be included in each of thetouch bending part BF2 and the touch non-bending part NBF2. Theconductive pattern CP has a grain size of about 10 nm to about 100 nm.The conductive pattern CP includes the conductive pattern layers CPL(refer to FIG. 2B), each having a grain size of about 10 nm to about 100nm.

The conductive pattern CP includes a sensing electrode TE, a firstconnection line TL1, a second connection line TL2, a first fanout linePO1, a second fanout line PO2, a first bridge BD1, and a second bridgeBD2, which will be described in detail later.

Referring to FIGS. 7A, 7B, 8A, and 8B, the sensing electrode TE isdisposed on the sealing layer SL. Although not shown in the figures, anadditional flexible substrate may be disposed between the sensingelectrode TE and the sealing layer SL. The sensing electrode has a grainsize of about 10 nm to about 100 nm.

The sensing electrode TE includes the first sensing electrodes Tx andthe second sensing electrodes Rx. The first sensing electrodes Tx areelectrically connected to each other and the second sensing electrodesRx are electrically connected to each other. Each of the first andsecond sensing electrodes Tx and Rx has a substantially lozenge, square,rectangular, or circular shape, or an atypical shape, e.g., a dendritestructure. Each of the first and second sensing electrodes Tx and Rx hasa mesh structure.

Referring to FIGS. 7A and 7B, the first sensing electrodes Tx aredisposed on a layer different from a layer on which the second sensingelectrodes Rx are disposed. For instance, the first sensing electrodesTx are disposed on the sealing layer SL and an insulating layer IL2 isdisposed on the first sensing electrodes Tx. The second sensingelectrodes Rx are disposed above the first sensing electrodes Tx.

The first sensing electrodes Tx extend in a fifth direction DR5 and arearranged to be spaced apart from each other in a sixth direction DR6.The second sensing electrodes Rx extend in the sixth direction DR6 andare arranged to be spaced apart from each other in the fifth directionDR5.

Referring to FIGS. 8A and 8B, the first and second sensing electrodes Txand Rx may be disposed on the same layer. The first and second sensingelectrodes Tx and Rx are disposed on the sealing layer SL. The firstsensing electrodes Tx are arranged in the fifth and sixth directions DR5and DR6 and spaced apart from each other.

The first sensing electrodes Tx spaced apart from each other in thefifth direction DR5 are connected to each other by the first bridge BD1.The second sensing electrodes Rx are arranged in the fifth and sixthdirections DR5 and DR6 and spaced apart from each other. The secondsensing electrodes Rx spaced apart from each other in the sixthdirection DR6 are connected to each other by the second bridge BD2. Thesecond bridge BD2 is disposed on the first bridge BD1. Although notshown in the figures, an insulating layer may be disposed between thefirst bridge BD1 and the second bridge BD2.

Each of the first and second bridges BD1 and BD2 has a grain size ofabout 10 nm to about 100 nm. Each of the first and second bridges BD1and BD2 includes a plurality of layers, each having a grain size ofabout 10 nm to about 100 nm. Each of the layers included in each of thefirst and second bridges BD1 and BD2 has a thickness of about 10 nm toabout 150 nm.

The connection lines TL1 and TL2 are electrically connected to thesensing electrode TE. The connection lines TL1 and TL2 have a grain sizeof about 10 nm to about 100 nm.

The connection lines TL1 and TL2 included first connection lines TL1 andsecond connection lines TL2. The first connection lines TL1 areconnected to the first sensing electrodes Tx and first fanout lines PO1.The second connection lines TL2 are connected to the second sensingelectrodes Rx and second fanout lines PO2.

The fanout lines PO1 and PO2 are connected to the connection lines TL1and TL2 and pad parts PD1 and PD2. The fanout lines PO1 and PO2 includethe first fanout lines PO1 and second fanout lines PO2. The first fanoutlines PO1 are connected to the first connection lines TL1 and the firstpad part PD1. The second fanout lines PO2 are connected to the secondconnection lines TL2 and the second pad part PD2.

The first and second pad parts PD1 and PD2 are electrically connected tothe sensing electrode TE. The first and second pad parts PD1 and PD2have a grain size of about 10 nm to about 100 nm. The first and secondpad parts PD1 and PD2 include a plurality of layers, each having a grainsize of about 10 nm to about 100 nm. Each of the layers included in thefirst and second pad parts PD1 and PD2 has a thickness of about 10 nm toabout 150 nm.

The pad parts PD1 and PD2 include the first pad part PD1 and the secondpad part PD2. The first pad part PD1 is connected to the first fanoutlines PO1. The first pad part PD1 is electrically connected to the firstsensing electrodes Tx. The second pad part PD2 is connected to thesecond fanout lines PO2. The second pad part PD2 is electricallyconnected to the second sensing electrodes Rx.

FIG. 9A is a cross-sectional view showing the sensing electrode TEincluded in a touch screen panel according to an exemplary embodiment ofthe present disclosure.

Referring to FIG. 9A, the sensing electrode TE includes a plurality ofsensing electrode layers TEL. The sensing electrode TE includes two,three, four, five, or six sensing electrode layers TEL, but it shouldnot be limited thereto or thereby. The sensing electrode TE may includeseven or more sensing electrode layers TEL. An air layer (not shown) maybe provided between the sensing electrode layers TEL.

Each of the sensing electrode layers TEL has a grain size of about 10 nmto about 100 nm. When the grain size of the sensing electrode layers TELis less than about 10 nm, a resistance of the sensing electrode layersTEL increases, and thus, power consumption required to drive theflexible display device 10 (refer to FIG. 5A) increases. When the grainsize of the sensing electrode layers TEL is greater than about 100 nm,it is difficult to secure flexibility of the bending of the sensingelectrode layers TEL since the grain size is excessively large. As aresult, a crack or a disconnection occurs in the sensing electrodelayers TEL, and reliability of the sensing electrode layers TEL isreduced.

Each of the sensing electrode layers TEL has a thickness of about 10 nmto abut 150 nm. When the thickness of each of the sensing electrodelayers TEL is less than about 10 nm, the number of interfaces of thesensing electrode layers TEL increases even though the overall thicknessof the sensing electrode TE is not increased, and thus, the resistanceof the sensing electrode TE increases. Accordingly, power consumptionrequired to drive the flexible display device 10 (refer to FIG. 5A)increases. In addition, the reliability of the sensing electrode layersTEL may be reduced when each sensing electrode layer TEL is manufacturedor provided. When the thickness of each of the sensing electrode layersTEL exceeds about 150 nm, it is difficult to secure flexibility of thesensing electrode layers TEL when the sensing electrode layers TEL arebent. As a result, a crack or a disconnection occurs in the sensingelectrode layers TEL and reliability of the sensing electrode layers TELis reduced.

Each of the sensing electrode layers TEL may include at least one of ametal, a metal alloy, and a transparent conductive oxide, but it shouldnot be limited thereto or thereby.

The metal may include, but not limited to, at least one of Al, Cu, Ti,Mo, Ag, Mg, Pt, Pd, Au, Ni, Nd, Ir, and Cr.

The transparent conductive oxide may include, but not limited to, atleast one of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide(ZnO), and indium tin zinc oxide (ITZO).

FIG. 9B is a cross-sectional view showing lines included in the touchscreen panel according to an exemplary embodiment of the presentdisclosure.

Referring to FIG. 9B, the lines TL1, TL2, PO1, and PO2 include aplurality of line layers TLL. The lines TL1, TL2, PO1, and PO2 includetwo, three, four, fifth, or sixth line layers TLL, but they should notbe limited thereto or thereby. The lines TL1, TL2, PO1, and PO2 mayinclude seven or more line layers TLL. An air layer (not shown) may beprovided between the line layers TLL.

Each of the line layers TLL has a grain size of about 10 nm to about 100nm. When the grain size of the line layers TLL is less than about 10 nm,a resistance of the line layers TLL increases, and thus, powerconsumption required to drive the flexible display device 10 (refer toFIG. 5A) increases. When the grain size of the line layers TLL isgreater than about 100 nm, it is difficult to secure flexibility of thebending of the line layers TLL since the grain size is too large. As aresult, a crack or a disconnection occurs in the line layers TLL andreliability of the line layers TLL is reduced.

Each of the line layers TLL has a thickness of about 10 nm to abut 150nm. When the thickness of each of the line layers TLL is less than about10 nm, the number of interfaces of the line layers TLL increases eventhough the overall thickness of the lines TL1, TL2, PO1, and PO2 is notincreased, and thus, the resistance of the lines TL1, TL2, PO1, and PO2increases. Accordingly, power consumption required to drive the flexibledisplay device 10 (refer to FIG. 5A) increases. In addition, thereliability of the line layers TLL may be reduced when each line layerTLL is manufactured or provided. When the thickness of each of the linelayers TLL is greater than about 150 nm, it is difficult to secureflexibility of the line layers TLL when the line layers TLL are bent. Asa result, a crack or a disconnection occurs in the line layers TLL andreliability of the line layers TLL is reduced.

Each of the line layers TLL may include at least one of a metal, a metalalloy, and a transparent conductive oxide, but it should not be limitedthereto or thereby.

The metal may include, but not limited to, at least one of Al, Cu, Ti,Mo, Ag, Mg, Pt, Pd, Au, Ni, Nd, Ir, and Cr.

The transparent conductive oxide may include, but not limited to, atleast one of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide(ZnO), and indium tin zinc oxide (ITZO).

A conductive pattern included in a conventional flexible display devicehas a grain size greater than that of the conductive pattern accordingto the present exemplary embodiment, and thus, it is difficult to securethe flexibility of the bending of the flexible display device.Accordingly, when the conventional flexible display device is repeatedlybent or unbent, the crack or disconnection occurs in the conductivepattern, and the reliability of the flexible display device is reduced.

In addition, when the conventional flexible display device is repeatedlybent or unbent in directions opposite to each other, the crack ordisconnection more often occurs in the conventional flexible displaydevice since it is difficult to secure the flexibility of the bending.

The conductive pattern included in the flexible display device accordingto the present exemplary embodiment has the above-mentioned grain sizeor includes the conductive pattern layers each having theabove-mentioned grain size, and thus, the flexible display device maysecure the flexibility of the bending thereof without increasing theresistance of the conductive pattern. Therefore, although the flexibledisplay device is repeatedly bent or unbent, the crack or disconnectionoccurring in the conductive pattern may be reduced. Thus, thereliability of the flexible display device according to the presentexemplary embodiment may be improved.

In addition, although the flexible display device according to thepresent exemplary embodiment is repeatedly bent or unbent in directionsopposite to each other, the crack or disconnection occurring in theconductive pattern may be reduced since the flexibility of the bendingof the flexibility display device is secured.

Hereinafter, a manufacturing method of the flexibility display deviceaccording to the present exemplary embodiment will be described indetail.

FIG. 10 is a flowchart showing a method of manufacturing the flexibledisplay device 10 according to an exemplary embodiment of the presentdisclosure.

Referring to FIGS. 1A to 1C, 2A, 2B, and 10, the manufacturing method ofthe flexible display device 10 includes preparing the flexible substrateFB (S100) and providing the conductive pattern CP having a grain size ofabout 10 nm to about 100 nm on the flexible substrate FB (S200).

The flexible substrate FB may include, but is not limited to, theplastic material or the organic polymer, e.g., polyethylene (PET),polyethylene naphthalate (PEN), polyimide, polyether sulfone, etc. Thematerial for the flexible substrate FB is selected in consideration ofmechanical strength, thermal stability, transparency, surfacesmoothness, ease of handling, water repellency, etc. The flexiblesubstrate FB may be transparent.

The conductive pattern CP is provided on the flexible substrate FB. Theproviding of the conductive pattern CP (S200) is performed by sputteringat least one of the metal, the metal alloy, and the transparentconductive oxide. For instance, the conductive pattern CP is formed bysputtering at least one of the metal, the metal alloy, and thetransparent conductive oxide at a room temperature during a time periodof about one minute to about three minutes.

The metal may include, but not limited to, at least one of Al, Cu, Ti,Mo, Ag, Mg, Pt, Pd, Au, Ni, Nd, Ir, and Cr.

The transparent conductive oxide may include, but not limited to, atleast one of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide(ZnO), and indium tin zinc oxide (ITZO).

In the providing of the conductive pattern CP (S200), when the grainsize of the conductive pattern CP is less than about 10 nm, theresistance of the conductive pattern CP increases, and thus, powerconsumption required to drive the flexible display device 10 increases.When the grain size of the conductive pattern CP is greater than about100 nm, it is difficult to secure flexibility of the bending of theconductive pattern CP since the grain size is excessively large. As aresult, a crack or a disconnection occurs in the conductive pattern CPand reliability of the flexible display device 10 is reduced.

The providing of the conductive pattern CP (S200) may include formingthe conductive pattern layers CPL, each having a grain size of about 10nm to about 100 nm. The providing of the conductive pattern CP (S200)may include forming a first conductive layer by sputtering at least oneof the metal, the metal alloy, and the transparent conductive oxide,forming a second conductive layer by sputtering at least one of themetal, the metal alloy, and the transparent conductive oxide on thefirst conductive layer, and etching portions of the first conductivelayer and second conductive layer using a mask to form the conductivepattern.

When the grain size of the conductive pattern layers CPL is less thanabout 10 nm, the resistance of the conductive pattern layers CPLincreases, and thus, power consumption required to drive the flexibledisplay device 10 increases. When the grain size of the conductivepattern layers CPL is greater than about 100 nm, it is difficult tosecure flexibility of the bending of the conductive pattern layers CPLsince the grain size is excessively large. As a result, the crack ordisconnection occurs in the conductive pattern layers CPL andreliability of the flexible display device 10 is reduced.

Each of the conductive pattern layers CPL has a thickness of about 10 nmto abut 150 nm. When the thickness of each of the conductive patternlayers CPL is less than about 10 nm, the number of interfaces of theconductive pattern layers CPL increases even though the overallthickness of the conductive pattern CP is not increased, and thus, theresistance of the conductive pattern CP increases. Accordingly, powerconsumption required to drive the flexible display device 10 increases.In addition, the reliability of the conductive pattern layers CPL may bereduced when each conductive pattern layer CPL is manufactured orprovided. When the thickness of each of the conductive pattern layersCPL is greater than about 150 nm, it is difficult to secure flexibilityof the conductive pattern layers CPL when the conductive pattern layersCPL are bent. As a result, a crack or a disconnection occurs in theconductive pattern layers CPL and reliability of the conductive patternlayers CPL is reduced.

Each of the conductive pattern layers CPL may include at least one ofthe metal, the metal alloy, and the transparent conductive oxide, but itshould not be limited thereto or thereby.

The metal may include, but not limited to, at least one of Al, Cu, Ti,Mo, Ag, Mg, Pt, Pd, Au, Ni, Nd, Ir, and Cr.

The transparent conductive oxide may include, but not limited to, atleast one of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide(ZnO), and indium tin zinc oxide (ITZO).

A conductive pattern included in a conventional flexible display devicehas a grain size greater than that of the conductive pattern accordingto the present exemplary embodiment, and thus, it is difficult to securethe flexibility of the bending of the conventional flexible displaydevice. Accordingly, when the conventional flexible display device isrepeatedly bent or unbent, the crack or disconnection occurs in theconductive pattern and the reliability of the flexible display device isreduced.

In addition, when the conventional flexible display device is repeatedlybent or unbent in directions opposite to each other, the crack ordisconnection more often occurs in the conventional flexible displaydevice since it is difficult to secure the flexibility of the bending.

The conductive pattern included in the flexible display device accordingto the present exemplary embodiment has the above-mentioned grain sizeor includes the conductive pattern layers each having theabove-mentioned grain size, and thus, the flexible display device maysecure the flexibility of the bending thereof without increasing theresistance of the conductive pattern. Therefore, although the flexibledisplay device is repeatedly bent or unbent, the likelihood of a crackor a disconnection occurring in the conductive pattern may be reduced.Thus, the reliability of the flexible display device according to thepresent exemplary embodiment may be improved.

In addition, although the flexible display device according to thepresent exemplary embodiment is repeatedly bent or unbent in directionsopposite to each other, the the likelihood of a crack or a disconnectionoccurring in the conductive pattern may be reduced since the flexibilityof the bending of the flexibility display device is secured.

Hereinafter, the flexible display device according to the presentdisclosure will be described in detail with reference to variousembodiment examples.

FIGS. 11A and 11B are SEM images showing first to fourth embodimentexamples and first and second comparison examples, FIG. 12 is aphotograph showing a cross section of first and second embodimentexamples and first and second comparison examples, and FIG. 13 is aphotograph showing a disconnection in first and second comparisonexamples due to inner and outer bendings.

EMBODIMENT EXAMPLE 1

The conductive pattern was formed by sputtering aluminum on apolycarbonate (PC) substrate. The insulating layer was formed on theconductive pattern.

EMBODIMENT EXAMPLE 2

The conductive pattern was formed through the same process as that shownin Embodiment Example 1 except that the conductive pattern formed ofaluminum has a thickness of about 100 nm.

EMBODIMENT EXAMPLE 3

A process of sputtering aluminum on the polycarbonate (PC) substrate ata temperature of about 60° C. during about two minutes was performed sixtimes to form six conductive pattern layers, and thus, the conductivepattern including six conductive pattern layers, each having a thicknessof about 50 nm, was formed.

EMBODIMENT EXAMPLE 4

The conductive pattern was formed through the same process as that shownin Embodiment example 3 except that the sputtering process was performedat a temperature of about 20° C. rather than about 60° C.

EMBODIMENT EXAMPLE 5

A process of sputtering copper on a polycarbonate (PC) substrate isperformed six times on a polycarbonate (PC) substrate to form aconductive pattern layer having a thickness of about 50 nm, and theconductive pattern including six conductive pattern layers was formed.

EMBODIMENT EXAMPLE 6

A first Al conductive pattern layer having a thickness of about 150 nmwas formed by sputtering aluminum on a polycarbonate (PC) substrate, aTi conductive pattern layer having a thickness of about 5 nm was formedby sputtering titanium on the first Al conductive pattern layer, and asecond Al conductive pattern layer having a thickness of about 150 nmwas formed by sputtering aluminum on the Ti conductive pattern layer.

EMBODIMENT EXAMPLE 7

A first Al conductive pattern layer having a thickness of about 100 nmwas formed by sputtering aluminum on a polycarbonate (PC) substrate, aCu conductive pattern layer having a thickness of about 100 nm wasformed by sputtering copper on the first Al conductive pattern layer,and a second Al conductive pattern layer having a thickness of about 100nm was formed by sputtering aluminum on the Cu conductive pattern layer.

EMBODIMENT EXAMPLE 8

A Ti conductive pattern layer having a thickness of about 20 nm wasformed by sputtering titanium on a polycarbonate (PC) substrate, a Cuconductive pattern layer having a thickness of about 150 nm was formedby sputtering copper on the Ti conductive pattern layer, and an Alconductive pattern layer having a thickness of about 150 nm was formedby sputtering aluminum on the Cu conductive pattern layer.

COMPARISON EXAMPLE 1

The conductive pattern was formed through the same process as shown inEmbodiment example 1 except that the process of sputtering aluminum onthe polycarbonate (PC) substrate was performed at the temperature 60° C.during about two minutes and the conductive pattern has a thickness ofabout 300 nm.

COMPARISON EXAMPLE 2

The conductive pattern was formed through the same process as that shownin Comparison example 1 except that the sputtering process was performedat a temperature of about 20° C. rather than about 60° C.

COMPARISON EXAMPLE 3

The conductive pattern was formed through the same process as that shownin Embodiment example 1 except that the conductive pattern formed bysputtering aluminum on a polycarbonate (PC) substrate has a thickness200 nm.

1. Measurement

1) Measurement of the grain size

The grain size was measured by taking a scanning electron microscope(SEM) image of a cross section of Embodiment examples 1 to 3, Embodimentexamples 5 to 8, and Comparison examples 1 and 2. The SEM image wastaken by using Helios 450, FEI Co. The SEM images are shown in FIGS. 11Aand 11B and the grain size is represented by the following Table 1. Inaddition, SEM images of cross sections of Embodiment examples 3 and 4and comparison examples 1 and 2 are shown in FIG. 12.

TABLE 1 Grain size (nm) Embodiment example 1 29 Embodiment example 2 58Embodiment example 3 32 Embodiment example 5 38.6 Embodiment example 697.7 Embodiment example 7 69.9 Embodiment example 8 88.1 Comparisonexample 1 196 Comparison example 2 119

2) Measurement of the Number of the Grains

The number of the grains arranged within a unit area of about 1.0 squaremicrometers (μm²) was measured by taking an SEM image of the conductivepattern of Embodiments 1 and 2 and Comparison examples 1 and 2. Thenumber of the grains is represented by the following Table 2.

TABLE 2 Number of grains Embodiment example 1 1189 Embodiment example 2297 Comparison example 1 26 Comparison example 2 71

3) Check whether the Disconnection Occurs Due to the Inner Bending andthe Outer Bending

The disconnections due to the inner bending and the outer bending ofEmbodiment examples 1 to 8 and Comparison examples 1 and 3 were checked.The disconnections due to the inner bending in Comparison examples 1 and3 are shown in FIG. 13.

4) Measurement of a Resistance Variation Due to the Inner Bending andthe Outer Bending

The resistance variation due to the inner bending in Embodiment examples1 and 2 and Comparison examples 1, 2, and 5 and the resistance variationdue to the outer bending in Embodiment examples 1 and 2 and Comparisonexamples 1 and 3 were measured. The resistance variation due to theinner bending is represented by the following Table 3 and the resistancevariation due to the outer bending is represented by the following Table4.

TABLE 3 Resistance variation (%) Number Embod- Embod- Embod- Compar-Compar- of inner iment iment iment ison ison bendings example 1 example2 example 5 example 1 example 3 0 0 0 0 0 0 50000 0 0 0 500 0 100000 0 00 500 9 150000 0 0 0 500 19 200000 0 0 0 500 24

TABLE 4 Resistance variation (%) Number Embod- Embod- Embod- Compar-Compar- of outer iment iment iment ison ison bendings example 1 example2 example 5 example 1 example 3 0 0 0 0 0 0 50000 0 0 0 303 0 100000 2 45 448 11 150000 3 6 5 506 27 200000 3 10 5 528 54

2. Measurement Result

1) Measurement of the Grain Size

Referring to FIGS. 11A, 11B, and 12 and Table 1, the grain size of eachof Embodiment examples 1 to 8 was less than the grain size of each ofComparison examples 1 and 2.

2) Measurement of the Number of

As represented by Table 2, the number of the grains of Embodimentexamples 1 and 2 was less than the number of the grains of Comparisonexamples 1 and 3.

3) Check whether the Disconnection Occurs Due to the Inner Bending andthe Outer Bending

The disconnections due to the inner bending and the outer bending do notoccur in Embodiment examples 1 to 8, but the disconnections due to theinner bending and the outer bending occur in Comparison examples 1 and 3as shown in FIG. 13.

4) Measurement of a Resistance Variation Caused by the Inner Bending andthe Outer Bending

Referring to Tables 3 and 4, the variation in resistance due to theinner bending is and the outer bending was relatively small inEmbodiment Examples 1, 2, and 5, but the variation in resistance due tothe inner bending and the outer bending was relatively large inComparison Examples 1 and 3.

According to the above, the likelihood of an occurrence of the crack dueto the bending may be reduced. In addition, the flexible display device,in which the occurrence of the crack due to the bending is reduced, maybe manufactured.

Although certain exemplary embodiments and implementations have beendescribed herein, other embodiments and modifications will be apparentfrom this description. Accordingly, the inventive concept is not limitedto such embodiments, but rather to the broader scope of the presentedclaims and various obvious modifications and equivalent arrangements.

What is claimed is:
 1. A flexible display device comprising: a flexibledisplay panel comprising a panel bending part; and a touch screen panelcomprising a touch bending part and disposed on the flexible displaypanel, wherein at least one of the flexible display panel and the touchscreen panel comprises a conductive pattern comprising a plurality ofconductive pattern layers, each of the conductive pattern layers havinga grain size of about 10 nm to about 100 nm, and at least one of thepanel bending part and the touch bending part comprises the conductivepattern.
 2. The flexible display device of claim 1, wherein theconductive pattern comprises at least one of a metal, an alloy of themetal, and a transparent conductive oxide.
 3. The flexible displaydevice of claim 1, wherein each of the conductive pattern layers has athickness of about 10 nm to about 150 nm.
 4. The flexible display deviceof claim 1, wherein the flexible display panel comprises: a plurality ofgate lines; a plurality of data lines electrically connected to the gatelines; and a plurality of pixels each being connected to at least one ofthe gate lines and at least one of the data lines, wherein at least oneof the gate lines and the data lines comprises the conductive pattern.5. The flexible display device of claim 4, wherein: each of the pixelscomprises a thin film transistor comprising a semiconductor pattern, asource electrode electrically connected to the semiconductor pattern,and a drain electrode spaced apart from the source electrode; and atleast one the semiconductor, the source electrode, and the drainelectrode comprises the conductive pattern.
 6. The flexible displaydevice of claim 1, wherein the touch screen panel comprises: a sensingelectrode; a pad part electrically connected to the sensing electrode; aconnection line connected to the sensing electrode; and a fanout lineconnected to the connection line and the pad part, wherein at least oneof the sensing electrode, the pad part, the connection line, and thefanout line comprises the conductive pattern.
 7. The flexible displaydevice of claim 6, wherein the sensing electrode comprises a meshstructure.
 8. The flexible display device of claim 1, wherein theflexible display device is configured to operate in one of a: first modein which at least a portion of the conductive pattern is bent; and asecond mode in which the bent portion of the conductive pattern isunbent.
 9. The flexible display device of claim 8, wherein the firstmode comprises: a first bending mode in which the conductive pattern isbent in one direction with respect to a bending axis; and a secondbending mode in which the conductive pattern is bent in a directionopposite to the one direction with respect to the bending axis.
 10. Aflexible display device comprising: a flexible display panel; and atouch screen panel comprising a touch bending part, wherein: the touchbending part comprises a sensing electrode comprising a mesh structure;the sensing electrode comprises a plurality of sensing electrode layers;and the sensing electrode layers comprise a same material.
 11. Theflexible display device of claim 10, wherein the material comprises oneof Al, Cu, Ti, Mo, Ag, Mg, Pt, Pd, Au, Ni, Nd, Ir, and Cr.
 12. Theflexible display device of claim 10, wherein each of the sensingelectrode layers has a grain size of about 10 nm to about 100 nm. 13.The flexible display device of claim 10, wherein each of the sensingelectrode layers has a thickness of about 10 nm to about 150 nm.
 14. Theflexible display device of claim 10, wherein: the flexible displaydevice is configured to operate in one of: a first mode in which atleast a portion of the flexible substrate and the conductive pattern isbent; and a second mode in which then bent portion of the flexiblesubstrate and the conductive pattern is unbent; and the first modecomprises: a first bending mode in which the flexible substrate and theconductive pattern are bent in one direction with respect to a bendingaxis; and a second bending mode in which the flexible substrate and theconductive pattern are bent in a direction opposite to the one directionwith respect to the bending axis.